Lithographic dampening mechanism and method



Nov. 24,. 1959 R. E. LINDEMANN 2,913,930

LITHOGRAPHIC DAMPENING MECHANISM AND METHOD Filed Nov. 27, 1957 3Sheets-Sheet 1 SUPPLY TA K INVENTOR. ROBERT E.LINDEMANN u/M M1 7" Nov.24, 1959 R. E. LINDEMANN 2,913,980

LITHOGRAPHIC DAMPENING MECHANISM AND METHOD Filed Nov. 27, 1957 sSheets- Sheet 2 INVENTOR. ROBERT E.LINDEMANN AGENT R. E. LINDEMANNLITHOGRAPHIC DAMPENING MECHANISM AND METHOD Nov. 24, 1959 S Sheets-Sheet3 Filed Nov. 27, 1957 INVENTOR. ROBERT E. LINDEMANN AGENT United StatesPatent ce LITHOGRAPHIC DAMPENING MECHANIS AND METHOD Robert E.Lindemann, Medina, Ohio, assignor to Harris- Intertype Corporation,Cleveland, Ohio, a corporation of Delaware Application November 27,1957, Serial No. 699,316

12 Claims. (Cl. 101- 1'48) charging a predetermined amount of the liquidto its sur' face for subsequent presentation to a lithographic printingplate of the press.

Another object of the invention is to provide that such member be a rollconstructed of individual transverse cells or sections, each cell havingvariable means for passing a measured amount of liquidto its surface,thus enabling control of the quantity of liquid across the width of theroll and ultimately across the lithographic plate.

A further object of the invention is to provide novel means for cleaningand draining the individual sections of the roll.

Other objects and advantages will be apparent from the followingdescription in which reference is made to the accompanying drawings.

According to a preferred form of the invention, a hollow tube hasconcentrically mounted thereover with a space therebetween a series ofporous bushings with means dividing the bushings laterally intoindividual cells. Liquid is communicated to and fills the space betweenthe tube and each bushing. Between a supply for the liquid and eachbushing is a pump which intermittently adds a preselected amount ofliquid to the space between the bushing and roll and thereby displaces alike amount of liquid by passing it to the surface of the bushing.Liquid so passed to the surface is then transferred directly orindirectly to a lithographic plate to dampen the plate prior to itsbeing inked.

In the drawings:

Fig. 1 is a fragmentary elevational view of a preferred form of theinvention.

Fig. 2 is a fragmentary elevational view on a larger scale taken lookingfrom the left side of Fig. l.

1 Fig. 3 is a fragmentary view somewhat similar to the left end of Fig.1, and is taken along lines 33 of Fig. 2.

Fig. 4 is an enlarged detailed view of a pump constituting a portion ofthe invention.

Fig. 5 is a simplified side elevational view illustrating one type ofdampening roll arrangement with which the invention may be used.

Fig. 6 shows another dampening roll arrangement with which the inventionmay be used.

Referring now to Fig. 1, spaced side supports 10 and 11 of alithographic printing press rotatably support a tube tube 12 and fixedthereto.

or roll 12. The tube has mounted at one end thereof a rotary union 18,the purpose of which will be described v later. The pipe 17 rotates withthe tube 12 when driven by the gear 14. On the opposite end of the tubeis mounted a pump assembly 19 into which is threaded a plurality ofpiston assemblies 20. For reasons which will become apparent later, thepiston assemblies are spaced equidistant around the assembly 19 and arelocated in planes offset axially with respect to the tube 12. The pumpassembly 19 comprises a first cap 21 fixed to the tube 12, a chamberedannular member 22, a cap 23 secured to the chambered annular member, andan end piece 24 secured to the cap 23. A short length of pipe 25 isthreaded into the end piece 24 similarly to the connection at theopposite end of the tube. The pipe 25- comprises a portion of a rotaryunion 26 through which liquid from a supply tank 27 (shownschematically) is communicated to the exterior of the portion of thetube 12 between the side supports10 and 11 as will now be described.

The dampening medium of the present invention, that is, the means whichactually supplies liquid to the litho graphic plate of the printingpress is shown generally as a roll 28. In the preferred form of theinvention, this dampening medium comprises a plurality of porousbushings 29 mounted between rings 30 spaced axially onthe It will benoticed that each of the porous bushings 29 is counter-bored at its endsin order to properly fit over the rings 30. The porous bushings may bemade of cast metal powder such as *Oilite stainless steel. A cover 31fits over the bushings 29 and is made of the material known as Molletonin the trade. It will be shown in another modification of the inventionhowever that the cover 31 is not an essential part of the invention.

The bushings 29 are concentric with the tube 12 and have a space betweenthem and the tube. Communicating from each individual cell to the cap 21is a pipe 32. The pipes are spaced around the interior of the tube 12and are fastened to the cap 21 by welding or other means. In the formofthe invention shown, there are eight such pipes and eight bushings 29,dividing the roll crosswise into eight individual cells. Angularlyoffset openings 33 are provided in the cap 21 and corresponding openingsor chambers 34 are provided in the annular member 22. The openings 33and 34 communicate with their respective pipes 32.

Ink repellent dampening material in the supply tank 27 is communicatedby gravity or pump through piping 35 to the rotary union 26, through thepipe 25 to a chamber 36 counterbored into the end piece 24. The chamber36 encompasses all of the openings 34 in the annular member 22.Intermediate the member 22 and the end piece 24 is a filter 37 forpreventing entrance of foreign substance into the roll proper. Thisfilter may be dispensed with under certain circumstances where it is'notneeded or desired to be used.

Each of the chambers 34 is provided with one of the piston assemblies20, a one-way inlet valve 38, and a oneway outlet valve 39. The pistonassembly 20 comprises a piston 40 which is spring urged in one directionand cam urged in the opposite direction by means to be subsequentlydescribed. The piston 40 is positively actuated to displace a portion ofthe liquid in the chamber 34so as to pass the displaced amount throughthe outlet valve 39 and then through the corresponding opening 33 inpipe 32 to and through the proper porous bushing 29 to dampen the cover31. On its return stroke caused by the action of a spring 41, the pistonwill draw through the inlet valve 38 from the chamber 36 a sufiicientamount of the liquid to maintain that particular chamber 34 completelyfull. It will be seen that each of the chambers of the roll 28 may thusbe provided with what amounts to an intermittent pressure so as to passa predetermined amount .of liquid through the porous medium of thebushings 29, To

Patented Nov. 24, 1959 determine the amount of liquid so passed, a camshoe 42 is provided to be engaged by the stem of the piston 40. The stemextends radially outward from the annular member 22. The camshoe may beradially adjusted in andoutby means of a thumb nut 43 threaded onto ac-amcarrier 44 which supports the cam shoe 42. This mechanism will bedescribed in more detail in the descrip tion ofFig. 4.

When a printing job has been completed the roll may be cleaned asfollows. A supply of air pressure is communicatedto apipe 45 having ashut-off valve 46. When the valve 46 is opened, air under pressure willpass through the rotary union 18 and theshort pipe 17 to the interior ofthe tube 12. For each cell or chamber in the roll, i.e. the sectionsbetween the several rings 30, there is provided a one-way valve 47opening from the interior to thej exterior of the tube 12. A petcock 48for each opening33 is opened to permit draining. of. the liquid fromwithin the roll. A collector 49 having a funnel, top 50 is located toalign with the petcocks 48'. When draining, the petcocks are opened oneat a time, that one directly pointing. downwardly toward the funnel 50being opened and the roll being maintained stationary. The air pressurethen passing through the pipe 45 communicates to the interior of thetube 12 and acts to open the valve 47 so as to blow air through thevalve. This causes liquid in the chamber to pass through its pipe 32 tothe opening 33 and then out through its petcock 48. Each of the pipes 32has a radial portion 51 which ends very closeto the inner surface of thebushing 29. In this fashion, when air pressure isv introduced into thearea normally filled with liquid, almost all of the liquid is passed outthrough the portion 51 of the pipe 32. When so cleaning the roll, liquidismaintained in the chambers 34 of the annular member 22 since theone-way valve 39 will permit passage of the liquid in only onedirection. Referring now to Fig. 2, roll' 28 may run in contact with aplate mounted on a plate cylinder 52. Also running in contact with theplate cylinder are a plurality of the customary inking form rolls 53. Avibrating storage roll 54 receives ink through a train of rollers froman ink fountain (not shown) and passes the ink to the form rolls 53. Therolls 53 lay the ink. onto the plate on the plate cylinder 52 after the,dampening means has dampened the surface of the plate.

Carried, on the framework of the printing press is the dampening unit ofwhich the present invention is a. part. A rack 55 is fixed to a frame 56of the machine at each side thereof. A dampening unit is mounted to bemovable toward and away from the plate cylinder 52 as a unit byproviding that a pinion 57 in mesh with the rack 55 at each. end of themachine enable the entire dampening unit move as a. carriage. Thepinions 57 are keyed to a shaft 58 extending parallel to the roll 28 andare journaled in side members 59. A handle 60 is also fixed to the shaft58 and may be turned so as to cause the pinions 57 to ride on the racksand move, the dampening unit to and from. the plate cylinder. A notchedannular piece 61 is fixed to the shaft 58 and is adapted to receive inits notch 62. a detent 63 which is spring urged radially inward of theshaft" 58'. The detent 63 is mounted for endwise movement in a bracket64 carried on the member 59 on the leftjside of the machine as viewed inFig. 1. The angles in the notch 62 are such as will permit the detent tobe urged outwardly from the notch 62 by applying a sufficient. amount ofpressure to the handle 60 to move theunit to: and from the platecylinder 52. Riding on. the pump assembly 19 but maintained againstrotation is: a cam shoe holder 65. It has sides 66 and 67 and aconcentric portion 68 (see Fig. l). The shoe holder 65 is maintainedagainst rotation by being provided with an ear 69'having a slot 70 whichencompasses a protruding end of a rod 71 extending laterally outwardfrom the member 59.

It will be seen in Fig. 2 that there are eight piston as- 4 semblies 20,a like number of the openings 34 in the annular member 22, and a likenumber of cam shoes 42 with their adjusting means. It will be seen thateach piston assembly 20 is radially outward of one of the chambers 34.The thumb nut 43 used to adjust each shoe 42 is knurled to permit itshand adjustment. To provide for even application of the dampening fluidacross the individual sections of the roll 28, a vibrator roll 72 may beprovided. Vibration of this roll is effected from the vibration ofthe-roll -54 engaging the form rolls 53 of the inker. A frame member 73of the inker has a projecting portion which carries a block 74 extendingoutwardly parallel to the tube 12. A, lever 75 is pivoted on an upwardlydirected pin 76 in the block 74 and carries at its opposite end a roller77 riding between the sides of a collar 78. The collar 78 is mounted onthe end of a shaft 79 extending outwardly of the vibrating storageroller 54. As shown in Fig. 3, the lever 75 has a bifurcated portion 80between the arms of which is mounted a pin 81 on which is journaled, alever 82. The lever 82 carries at its outer end a roller 83 which fitsbetween the sides of a collar 84 mounted on a shaft 85 fixed to thevibrator roll 72. The roll 72 is journaled in bearings 86 only one ofwhich is shown in Fig. 3. The bearings 86 are capable of floating andare urged toward the roll 28 by means of springs 87. The bearings 86 arecarried on rods 88 which are fastened to blocks 89 by means of nuts 90.The blocks 89 are mounted on the framework of the dampening unit.

It will be noted that the rod 71 extends between the members 59 and isnumbered across its length as shown in Fig. 3. These numbers correspondto the various sections of the roll divided by the rings 30 shown indotted lines. It will be noted at the left of Fig. 3 that the screwsthat carry the cam shoes 42 are also stamped with a number to indicatewhich shoe corresponds to its section of the roll 28. Each of the nuts43 is stamped with numbers which indicate the extent of the adjustmentof its shoe 42 toward and away from the stem of the piston 40 of thepiston assembly 20 to determine the amount of liquid pumped for eachrotation of the tube 12 in accordance with the stroke of the piston.Pins 91 having points closely adjacent the side of the nuts 43 show thesettings for the various sections of the dampening roll.

In a particular printing job, it may be found that one side of thesubject matter to be printed will require very heavy ink and/ordampening solution whereas the other side will require only a little.The amount of liquid passed through the various sections of thedampening member may be adjusted through the nuts 43. Obviously, theamount of solution supplied to the plate for any printing job can becontrolled across the width of the plate.

Referring now to Fig. 4, it will be seen that the shoes 42 are carriedon a member 92 which approximately comprises an inverted T. A pair ofpins 93 extend radially outward of the center of the pump assembly 19and are fixed in the arms of the T-shaped member 92. These pins areguided by holes 94 in the concentric portion 68 of the shoe holder 65.Springs 95 surround the pins 93 and have their ends abut the arms of theT and the bottom of a counterbore 96. It will be seen that adjustment ofa nut 43 will move its cam shoe 42 in or out. The cam surface of theseshoes is slightly eccentric with respect to the axis of the tube 12. Inthis manner the portions 97 of the pistons 40 will first ride beneaththe cam surface of the shoe, will then engage the shoe and will bedepressed gradually to provide an even pumping of the liquid from thechamber 34 to the surface of the porous bushing 29 with which thatparticular chamber corresponds.

Referring now to Figs. 5 and 6, other roll arrangements with which theinvention may be used are illustrated. In Fig. 5', a pair of molletonrolls 98 run in contact with the plate on the plate cylinder 52. Theroll 28 does not have .a molleton covering in this instance. While it isbelieved that this modification wilI perform substantially well, thereis a possibility that with certain types of ink, the ink from the plateon the plate cylinder 52 may be picked up in part by the molletoncoverings of the molleton rolls 98 and passed to the surface of the roll28. In this fashion, it may be possible that the pores of the roll wouldbe clogged to a limited extent.

In Fig. 6, the rolls 98 run in contact with the plate on the platecylinder and in addition the customary metal vibrating roll 99 runs incontact with the two rolls 98'. The roll 28 in this instance runs incontact with the vibrating roll 99 to pass liquid from its surface tothe roll 99 and thence to the molleton rolls 98 and the plate.

It has been found that if the dampening member 28 is covered with azippered plastic covering overnight, the entire dampening mechanism willimmediately start performing properly upon starting up the press thefollowing morning. The usual filling of a roll pan and running thefountain for a somewhat lengthy period to printing has been overcomethrough use of the present invention.

Furthermore, while the preferred form illustrates a roll which iscompletely filled with liquid, a roll which is only partly filled willperform satisfactorily provided a partial vacuum is maintained on theliquid. While it is recognized that certain design difficulties may beencountered in producing such a mechanism, it is believed to be withinthe scope of mechanical skill and intended to be within the scope of theclaims.

Various modifications may be made Without departing from the spirit andscope of the invention.

Having thus described my invention, I claim:

1. In a device for applying ink repellent dampening fluid to a surfaceto be dampened in a lithographic printing press, a rotatable tubularroll having a pervious wall, said roll having means forming apluralityof independent enclosed chambers along its axis, a fluidsupply, means communicating the fluid supply to each of the chambers, afluid pump comprising a piston cooperating with the fluid to eachchamber, said pumps being carried by the roll, means for operating saidpumps as the roll rotates, and selectively operable means connected tosaid pump operatnig means for varying the length of stroke of eachpiston and consequently the quantity of liquid passed to the surface ofthe roll from each chamber.

2. A device according to claim 1 including a supply chamber in said rollon the fluid supply side of the pistons, and a rotary union connectingsaid supply chamber with the fluid supply.

3. A device according to claim 1 wherein each piston is axially offsetfrom the others along said roll, and wherein said pump operating meansincludes a stationary cam for operating each piston as the roll rotates.

4. A device according to claim 3 wherein the selectively operable meanscomprises means for adjusting each stationary cam radially relative toits piston.

5. A device according to claim 2 including a one-way outlet valveintermediate each piston and its corresponding roll chamber and aone-way inlet valve intermediate each piston and the roll supplychamber, and means for draining the roll chambers.

6. A device according to claim 5 wherein the draining means includes avalved opening from each roll chamber to atmosphere, and means forapplying pressure greater than atmospheric to each of the roll chambers.

7. In a device for applying ink repellent dampening fluid to a surfaceto be dampened in a lithographic printing press, a rotatable tubularroll having a pervious wall, said roll having a plurality of independentenclosed chambers along its axis, means supporting said roll forrotation on its axis, a fluid supply remote from said roll, a pumpassembly mounted on and rotatable with said roll, a fluid chamber insaid pump assembly, a rotary union and fluid conducting means connectingsaid fluid chamber with the fluid supply, said pump assembly comprisingindividual pump chambers connecting each roll chamber with the fluidchamber, a piston extending from each pump chamber radially outward ofthe pump assembly, a stationary cam for operating each piston as theroll rotates, each cooperating piston and cam being axially offset withrespect to each other pair of the same, and means for adjusting each camradially relative to its piston.

8. A device according to claim 7 in which a check valve is provided onthe intake and outlet side of each pump chamber, and in which the rollchambers, pump chambers, and fluid chambers are maintained completelyfull of fluid during operation of the device.

9. A device according to claim 7 wherein said pervious roll is made upof short tubular sections generally corresponding in length to thelength of each roll chamber as measured along the axis of the roll, andwherein said short sections are supported on an inner impervious tubularroll extending between supporting means located outwardly of the shortsections.

10. A device according to claim 7 wherein the pump chambers are formedin an annular member comprising a portion of the pump assembly, andwherein the pump chambers are spaced equidistant from the axis of theroll and from each other.

11. A device according to claim 8 including means for opening each ofthe roll chambers to atmosphere, and air pressure applyingmeansconnected to the roll chambers for forcing liquid from the chambersoutwardly through the openings for draining the roll at the outlet sideof the pump chambers.

12. A device according to claim 11 wherein the pervious roll issupported on an inner impervious tubular roll extending betweensupporting means located outwardly of the pervious roll, and wherein aplurality of check valves one for each roll chamber are provided in saidinner tubular roll, said inner roll being connected to the air pressureapplying means whereby increased pressure in the inner roll will openthe check valves and force liquid in the roll chambers outwardly throughtheir respective openings when opened.

References Cited in the file of this patent UNITED STATES PATENTS TakatsFeb. 13, 1940

